Maybe some of the stuff at Hop Louie qualifies, though they also have non-Cantonese "favorites" too. Contrary to popular belief, Hop Louie has not been around forever, but only for something less than 25 years. (It's the building that's been around forever, for many years housing the Golden Pagoda restaurant.) Indeed that's the trouble with looking for a Paul's Kitchen type of place in Chinatown. I can't think of any restaurants there that have a continuous history going back to the old time Cantonese era. I guess Quon Bros. does have a history, but I don't know what kind of food they serve since they turned into a jazz venue.